Pressure device



March 26, 1957 J. MERCIER PRESSURE DEVICE Filed Feb. 3, 1954 INVENTORJean Meficzefl BY I ATTO R N EYS United States Patent In pressureaccumulators of the type: including a rigid container having a: pair ofports: atitswrespecti-ve ends with a deformable bladder aflixed. to.oneo-f said ports and separating two fluids such as gas and liquidunder.-

pressure, if, as the bladder expands to force liquid from the other ofsuch ports, the walliof the bladder. adjacent. the: free end thereofshould cont-act the wall of the container before the portion of thebladder adjacent its affixed end, pockets maybe formed filled withliquid which:

would not be'expelled from the container. Thus, the accumulator would beinefiicient in operation as only a pop tion ofthe liquid in thecontainer would be utilized.

Where the bladder of a pressure accumulator serves.

to close the liquid. outlet portwhen such bladder has ex.- panded in thecontainer to substantially its. maximum amount, if such bladder in itsinflated but. undistendjed. condition is of length substantially'equ-al.tothat of the;-

container, the liquid outlet portmay be closed before substantially-allof. the liquid is-expelled. If the bladder is considerably shorter thanthe container andupon ex:-: pansion of. the bladder, as fluid is forcedfrom the con-- tainer, when the major portion of the bladder wallengages the wall of the container, the free end of the bladder should beconsiderably spaced. fromthe liquid outlet port,

continued expansion of the bladder will causethe wall.

thereof to rub against the side wall. of the container with resultantbreakdown of such bladder; In addition, the lower end of the bladderwould have to stretch excessively to reach the liquidport {010101361116latter, thereby subjecting the bladder to high stress with likelihood ofrupture.

It is accordingly among the objects of the invention to provide apressure accumulator of relatively low cost, which mayreadily-befabricated and which will function without likelihood of'breakdown orrupture of the-deformable bladder therein and with assurance thatsubstantially all of the liquid will be expelled from the container.

According to the invention, these objects are accomplished by thearrangement and combination of elements hereinafter described andparticularly recited in the claims.

In the accompanying drawings in which are shown one or more of variouspossible embodiments of the several features of the invention,

Fig. 1 is a longitudinal sectional view of a pressure accumulator, and

Figs. 2, 3 and 4 are diagrammatic views illustrating the operation ofthe bladder.

Referring now to the drawings, the pressure accumulator desirablycomprises a container or pressure vessel 11, preferably of strong, rigidmaterial such as steel, cast aluminum or the like, capable ofwithstanding high pressure and having a gas inlet port 12 and a liquidport 13 therein preferably opposed to each other. The container 11 maybe spherical or cylindro-spherical as shown and has a collapsible andexpansible bladder 14 therein, desirably of resilient material such asrubber or synthetic plastic of like: physical characteristics,

distended but substantiallyunstretched. condition; is small erthan thecavity of the container ll and has; itslongb tudinal axis aligned withthe ports 12 and 13. As shown.-

in ..Fig.. l, thezbladder is: substantiallyconical inv contour along itslengthwith. the. thickness. of the bladderwall gradually decreasing fromthe larger diameteror mounted end thereof; shown at the; top-to.theopposite end thereof, the. latter enddesirably,beingmubstantiallyfiat as at 16 and. preferably thicker: than. adjacentwall portion of the bladder.

The bladder l i -is. rigidly aflixed inthe container 11 preferably bymeans of a.fitting.,21,.which; desirably-has.

a. substantially cylindrical s.tem.:.por. tion..2 2- with. a. base diskpresenting an outstanding lateral flange- 23, at one end, thereof, whichdesirably has. annular groove 2.4. in

its upper face 25 in which maybe-positionedthe thickened. ring 26 aboutthe mouth ofthe-bladder 14.. Thus, when the parts are assembled as.shown; in. Fig. l, the bladder may be securely clamped in. place'bymeans ofa nut. 28: screwed upon the protruding threaded stern of thefitting, an annular shoulder 29- adjacent the :root end: of the stemabutting against the. rim of the: gas inlet port 12 to prevent cuttingof the ring. .2'6 of .th-eubladderby excessive tightening of the nut; 1

Although the outlet port 13 of the accumulator could.v

be controlled. in any suitablemanner, in the. embodiment herein shown,.it is preferred to use the general construction shown in PatentNo.2,469,171 dated -M ay 3,v 194.9, by the. use. of which an outletclosureassembly.

31 alfixed in. said port 13 may be removed without like-- lihood ofinjury to. the mechanic:..- As shown in Fig. 1,

this. assembly desirably comprises a. housing 32, preferably.

a tubular member which desirably has an external anr. nular shoulder 33-atv the upper end. thereof of'fouter diameter less than that of port 13.A locking member. 34,-

illustratively a ringof. greater outer diameter thanwsaid leakagebetween the wall of port 13 and the outer wall of tubular member 32 whena nut 37 is screwed on. the. externally. threaded portion .38 of saidtubular member 32.

Desirably positioned in said. tubularmember 32. is-af poppet valvecomprising a valve head 41 adapted to seat on the beveled mouth 42 oftubular member 32 and having a stem 43 preferably for-med integraltherewith. Stem 43 is slidably mounted in bearing opening 44, desirablyin a disk 46 mounted in the bore of tubular member 32, said disk havinga plurality of openings 48 therethrough to permit the passage of fluid,said valve head being normally retained in open position by means of acoil spring 49 encompassing stem 43 between head 41 and disk 46. As theconstruction and operation of said outlet closure assembly per se formsno part of this invention it will not be further described.

With the construction above described 0f the bladder and the container,the distance of the partly inflated bladder as shown in Fig. 1, from theinner surface of the container 11, increases progressively from near thefixed end of the bladder toward the free end thereof, and the size,shape and elastic characteristics of the bladder are selected so that inthe further expansion of the bladder from its expanded but undistendedcondition shown, it will progressively engage such inner surface of thecontainer 11 from near the fixed end of the bladder toward its free end.

. l alte'ni: e.d.,lidar.v 26,; 1.9.57

trolling the liquid outlet port 13, is opened and the bladder 14 expandsto force liquid from port 13, no liquid pockets will be formed betweenthe bladder and the rigid wall of the container since the bladder isprogressively applied against such wall from the end thereof adjacentthe point of connection of the bladder thereto to the other end thereof.

As a result, substantially all of the fluid in the container 11 will beforced toward the outlet port 13 for expulsion therefrom.

When the bladder is in inflated but undistended condition the flatbottom 16 will act like a diaphragm to take up pulsation therebyavoiding stress on the side Wall por tion of the bladder.

When the bladder has expanded sufliciently to engage the valve head41,by reason of the large surface area at the flattened end of the bladderengaging said valve head, stresses will not be concentrated and suchbottom is desirably reinforced to prevent wear due to its abutmentagainst said valve head.

As the bladder expands to force liquid from the container, both itslength and diameter will increase. Inasmuch as the wall thicknessprogressively decreases from the upper end of the bladder to its lowerend, each succeeding portion of the side wall of the bladder willincrease in length at a greater rate than the previous portion asindicated in Fig. 2.

Thus, when the bladder is almost fully distended it will assume theposition shown in Fig. 3 and the portion :1 of the bladder will engagethe lower end of the container as at a".

With additional but still not full distension of the bladder, theportion e thereof will only have to stretch a relatively short distanceto move near the lower end of the container (Fig. 4) at which time thecentral or flat portion of the bladder will be against the valve head41. Hence, only a slight additional expansion of the bladder is required to move the valve head to seated position to close the port 13.

With the construction of the bladder herein described in which the wallthickness progressively decreases, no undue stretching stress is appliedto the portion e of the bladder as would occur if the wall thickness wasconstant or progressively increasing. In such latter cases the portion eof the bladder by reason of the limited elongation of such bladder wouldengage the'wall of the container at approximately the point z! and hencewould be stretched considerably with possible rupture to approach thepoint e'.

With the construction above described in which the bladder issubstantially conical and of decreasing wall thickness from near itsaffixed end to its free end, en-

trapment of liquid due tothe formation of pockets is substantiallyprecluded with resultant high efliciency in the operation of theaccumulator due to the utilization of substantially all of the liquid inthe container.

Furthermore, due to the decreasing wall thickness of the bladder, whichpermits each succeeding portion to increase in length at a greater ratethan the previous portion, the portion of the bladder at its lower endwill only have to stretch a relatively small amount before the outletport is sealed thereby avoiding stress on such lower portion which mightcause rupture of the bladder and failure of the unit.

As many changes could be made in the above construction, and manyapparently widely dilferent embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and 1 not in a limitingsense.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

l. A bladder for a pressure accumulator comprising a substantiallyconical hollow member of resilient deformable material having a port atone end and of greater diameter near said port than at the other end,said bladder having its side wall thickness progressively decreasingfrom the portion thereof of greater diameter toward said other end.

2. The combination set forth in claim 1 in which the wall thickness ofthe portion of said bladder adjacent said other end is greater than thatof the adjacent wall.

3. A pressure accumulator comprising a substantially cylindricalcontainer having a port at each end, a substantially conical hollowbladder of resilient deformable material in said container having a portat one end afiixed to one of the container ports, said bladder being ofgreater diameter near said port than at the other end, said bladderhaving its side wall thickness progressively decreasing from the portionthereof of greater diameter toward said other end, said bladder when insubstantially undistended condition having its longitudinal axis alignedwith both of the ports in said container and having its side wall spacedfrom the container wall substantially the major portion of the length ofsaid bladder.

References Cited in the file of this patefi'it UNITED STATES PATENTS2,397,796 Lippincott Apr. 2, 1946 2,469,171 Mercier et al lay 3, 19492,540,676 Johnson et al Feb. 6, 1951 2.604.118 Greer July 22. 1952

